Astroblog

Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Tuesday, May 26, 2015

The Sky This Week - Thursday May 28 to Thursday June 4

The Full Moon is Wednesday June 4. Venus
is prominent in
the twilight evening sky. Jupiter is the
brightest object in the evening sky once Venus has set. Saturn is in the
head of the Scorpion and is easily visible in the evening. The Moon is close to Saturn on June 1. Comet C/2015 G2 MASTER is visible in
binoculars in the evening.

The Full Moon is Wednesday June 4.

Early evening sky on Saturday May 30 looking north-west as seen from
Adelaide
at 18:30 ACST showing Venus, Jupiter and comet C/2015 G2. The location of comet C/2015 G2 MASTER is
shown with a circle. You will need binoculars to see it.
Jupiter is the brightest object
above the north-western horizon once Venus has set. (click
to embiggen).

Venus
is easy to see above the western horizon in the twilight. At nautical
twilight, an hour after sunset, it is around two hand-spans
above the horizon, and still visible at astronomical twilight.

During the week Venus draws closer to the stars Castor and Pollux, forming a line with them, heading for a meeting with Jupiter
later this month.

Jupiter
is easily seen in the evening sky. It is the brightest object
above the
northern horizon when twilight ends, and continues into the
north-western sky as the night goes on. It is between the bright
star Regulus in
the sickle of Leo (this forms the head of the constellation of the
Lion) and Pollux in Cancer. It is also not far from the rather nice
Beehive cluster in
Cancer, and looks very good in binoculars. Jupiter, Venus and Pollux
form a line in the sky. On the 24th the crescent Moon is close to
Jupiter.

Jupiter is
visible for most of the evening, sets just before 10 pm, and is high
enough for telescopic observation once twilight is over.
Jupiter's Moons will be putting on a good
display in both binoculars and small telescopes.

Comet C/2015 G2 MASTER is climbing in the evening sky fading as it goes.
It is below magnitude 6, and with the full Moon nearby
it is may be difficult to see with
binoculars, but should be fine in telescopes. In binoculars and modest telescopes the comet
will be a fuzzy blob.

The comet will move through Monocerous into Canis Minor
this week. A spotters map suitable for printing in black and white is here.

Evening sky on Monday June 1 looking east as seen from
Adelaide
at 20:00 ACST. Saturn is easily visible above the horizon in the head of the Scorpion. The Moon is close by on the 1st. The
inset shows the telescopic view of Saturn at this time. (click
to embiggen).

Saturn
is now easily visible around 7 pm near the head of the constellation of the Scorpion not far
from the bright red star Antares. The sight of the distinctive
constellation of the Scorpion curled above the horizon, with bright
Saturn in its head, is very nice indeed.

While Saturn is readily visible from around 19:00, it is best for
telescope observation from around 20:00 into the morning hours.

There are lots
of interesting things in the sky to view with a telescope. Especially
with Jupiter, Venus and Saturn in the sky. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Tuesday, May 19, 2015

The Sky This Week - Thursday May 21 to Thursday May 28

The First Quarter Moon is Tuesday May 26. Venus
is prominent in
the twilight evening sky. Jupiter is the
brightest object in the evening sky once Venus has set. It is visited by the crescent Moon on the
24t. Saturn is in the
head of the Scorpion and is easily visible in the evening. Comet C/2015 G2 MASTER is visible in
binoculars in the evening.

The First Quarter Moon is Tuesday May 26. The Moon is at apogee, when it is furthest from the Earth, on the 27th.

Early evening sky on Sunday May 24 looking north-west as seen from
Adelaide
at 18:30 ACST showing Venus, Jupiter and the crescent Moon. Jupiter is the brightest object
above the north-western horizon once Venus has set. (click
to embiggen).

Venus
is easy to see above the western horizon in the twilight. At nautical
twilight, an hour after sunset, it is around two hand-spans
above the horizon, and still visible at astronomical twilight.

During the week Venus draws closer to the stars Castor and Pollux, heading for a meeting with Jupiter
later next month.

Jupiter
is easily seen in the evening sky. It is the brightest object
above the
northern horizon when twilight ends, and continues into the north-western sky as the night goes on. It is between the bright
star Regulus in
the sickle of Leo (this forms the head of the constellation of the
Lion) and Pollux in Cancer. It is also not far from the rather nice Beehive cluster in
Cancer, and looks very good in binoculars. Jupiter, Venus and Pollux form a line in the sky. On the 24th the crescent Moon is close to Jupiter.

Jupiter was at
opposition, when it is biggest and brightest in our sky, on 7 February,
but
it will be an excellent object for many weeks to come. Jupiter is
visible for most of the night, setting just before 11 pm, and is high
enough for telescopic observation once twilight is over.
Jupiter's Moons will be putting on a good
display in both binoculars and small telescopes.

Evening sky on Saturday May 23 looking east as seen from
Adelaide
at 20:00 ACST. Saturn is easily visible above the horizon in the head of the Scorpion. The
inset shows the telescopic view of Saturn at this time. (click
to embiggen).

Saturn
is now easily visible around 9 pm near the head of the constellation of the Scorpion not far
from the bright red star Antares. The sight of the distinctive
constellation of the Scorpion curled above the horizon, with bright
Saturn in its head, is very nice indeed.

While Saturn is readily visible from around 19:00, it is best for
telescope observation from around 21:00 into the morning hours.

The evening sky at 18:55 (6:55 pm ACST) looking west as seen
from Adelaide on 23 May. The location of comet C/2015 G2 MASTER is
shown with a circle. You will need binoculars to see it.
Similar views will be seen elsewhere in Australia at
equivalent local times. (click on image to embiggen).

Comet C/2015 G2 MASTER is climbing in the evening sky fading as it goes. It should be just below magnitude 6, but with the waxing Moon nearby it is best viewed with
binoculars and telescopes. In binoculars and modest telescopes the comet will be a fuzzy blob, high power telescopes may show the thin tail seen in astrophotographs, although the Moon makes that unlikley.

The comet will move up through Canis Major towards Canis Minor
this week. A spotters map suitable for printing in black and white is here.

There are lots
of interesting things in the sky to view with a telescope. Especially
with Jupiter, Venus and Saturn in the sky. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Saturday, May 16, 2015

Aurora Watch (17-18 May)

An Aurora watch and a geomagnetic alert has been issued by the Australian IPS
for the 17 to 18th due to an anticipated impact from glancing blow from a
Coronal Mass Ejection interacting with a coronal hole solar wind stream. This
could translate into aurora at any time during the night time of the 17th to
early morning 18th. Aurora, if they flare up tonight, are likely to be seen
only in Tasmania (possibly Victoria).

Aurora can occur at any time after
nightfall (although around midnight or just after seems to be common). Dark sky
sites have the best chance of seeing anything, and always allow around 5 minutes
for your eyes to become dark adapted.

As always look to the south for
shifting red/green glows, beams have been reported consistently over the last
few aurora and a large green "blob" has been seen.

SUBJ: IPS AURORA WATCHISSUED AT 2330 UT ON 15 May 2015 BY IPS
RADIO AND SPACE SERVICESFROM THE AUSTRALIAN SPACE FORECAST CENTRE

A
glancing blow from a Coronal Mass Ejection is expected to impact theEarth
from late on 17-May. This, combined with coronal hole effects,could result
in significant space weather activity and visible aurorasduring local
nighttime hours on 17-May. Aurora alerts will followshould favourable space
weather activity eventuate.

Thursday, May 14, 2015

The path of comet C/2015 G2 MASTER from 14 to 21 May, looking west as seen from Adelaide at Astronomical twilight (6:50 pm) and hour an a half after sunset. The position of the comet is shown every two days. You will probably need binoculars to see it. Similar views will be seen elsewhere in Australia at
equivalent local times. Click to embiggen

Animation showing the path of the comet from 14-21 May at Astronomical twilight. Similar views will be seen elsewhere in Australia at
equivalent local times. Click to embiggen

Printable black and white horizon chart facing west an hour and a half after sunset showing the path of comet C/2015 G2 MASTER as seen from Adelaide. Similar views will be seen from
Southern Hemisphere locations at the equivalent local time. Click to
embiggen and print

A PDF spotters map also suitable for printing in black and white is here.

Printable black and white chart suitable for use with binoculars.

Comet C/2015 G2 MASTER has entered the evening sky after being a morning object. It is now high enough above
the horizon to be readily seen. It is around magnitude 6, just on
the threshold of unaided eye visibility, but is best viewed with
binoculars and telescopes. In binoculars the comet will looks like a large ball of cotton wool (it will look similar to the globular cluster omega centauri in binoculars). There is a thin tail seen in astrophotographs, but visual telescopic observation has not reported a tail yet.

The comet will move rapidly up through Lepus heading for Canis Major
this week. It will stay around magnitude 6 for most of this time, and be readily visible in binoculars. It is the only relatively bright fuzzy blob in the area.

From the 14th-17th if you sweep across to the left from Orion in binoculars you should pick it up fairly easily. There after sweep down and to the left from Sirius. On the 18th the comet will be in binocular range of the faint but pretty globular cluster M79, the comet being the brighter.

Wednesday, May 13, 2015

Aurora Alert NOW (13 May 2015)

An Aurora Alert and a geomagnetic alert has been issued by the Australian IPS
for the 13th due to an anticipated impact from a coronal hole solar wind stream.
This appears to have hit during daylight hours, but the geomagnetic storm may
continue during the evening hours.This could translate into aurora at any time
during the 13th. Glows have been reported, but Tasmania is suffering from cloud.

Currently, the Kindex is 4 (it's higher in the Hobart magnetometer, but
I suspect a glitch), solar wind speed is 535 Km/sec and the direction magnetic
field direction is southerly, only -4 nT, but this is favorable for developing
aurora. Aurora, if they flare up tonight, are likely to be seen only in Tasmania
(possibly Victoria).

Aurora can occur at any time after nightfall
(although around midnight or just after seems to be common). Dark sky sites have
the best chance of seeing anything, and always allow around 5 minutes for your
eyes to become dark adapted.

As always look to the south for shifting
red/green glows, beams have been reported consistently over the last few aurora
and a large green "blob" has been seen.

The Sky This Week - Thursday May 14 to Thursday May 21

The New Moon is Monday May 18. Venus
is prominent in
the twilight evening sky and is visited by the crescent Moon on the 21st. Jupiter is the
brightest object in the evening sky once Venus has set. Saturn is in the
head of the Scorpion and is easily visible in the evening. Mercury is difficult to view in the twilight. Comet C/2015 G2 MASTER is visible in binoculars in the evening.

The New Moon is Monday May 18. The Moon is at perigee, when it is closest to the Earth, on the 15th.

Evening sky on Tuesday May 19 looking west as seen from Adelaide
at 17:55 (5:55 pm) ACST in South Australia. Venus is obvious in the
early evening sky. Mercury is just on the horizon cloe to the crescent Moon. Similar views will be
seen
elsewhere
at the equivalent local time (click to embiggen).

Venus
is easy to see above the western horizon in the twilight. At nautical
twilight, an hour after sunset, it is around two hand-spans
above the horizon, and still visible at astronomical twilight.

During the week Venus draws closer to the stars Castor and Pollux, heading for a meeting with Jupiter
later next month. On the 21st the crescent Moon is close to Venus, forming a triangle with Venus and Pollux.

Mercury is low in the western evening sky and difficult to see in the twilight.On the 19th it and the crescent Moon are close, but you will need a flat level horizon like the ocean to see them.

Early evening sky on Thursday May 21 looking north-west as seen from
Adelaide
at 18:30 ACST showing Venus, the crescent Moon and Jupiter. Jupiter is the brightest object
above the north-western horizon once Venus has set. (click
to embiggen).

Jupiter
is easily seen in the evening sky. It is the brightest object
above the
northern horizon when twilight ends, and continues into the north-western sky as the night goes on. It is between the bright
star Regulus in
the sickle of Leo (this forms the head of the constellation of the
Lion) and Pollux in Cancer. It is also not far from the rather nice Beehive cluster in
Cancer, and looks very good in binoculars. Jupiter, Venus and Pollux form a line in the sky.

Jupiter was at
opposition, when it is biggest and brightest in our sky, on 7 February,
but
it will be an excellent object for many weeks to come. Jupiter is
visible for most of the night, setting just before 11 pm, and is high
enough for telescopic observation once twilight is over.
Jupiter's Moons will be putting on a good
display in both binoculars and small telescopes.

Evening sky on Saturday May 16 looking east as seen from
Adelaide
at 21:00 ACST. Saturn is easily visible above the horizon in the head of the Scorpion. The
inset shows the telescopic view of Saturn at this time. (click
to embiggen).

Saturn
is now easily visible around 9 pm near the head of the constellation of the Scorpion not far
from the bright red star Antares. The sight of the distinctive
constellation of the Scorpion curled above the horizon, with bright
Saturn in its head, is very nice indeed.

While Saturn is readily visible from around 20:00, it is best for
telescope observation from around 22:00 into the morning hours.

The evening sky at 18:55 (6:55 pm ACST) looking west as seen
from Adelaide on 14 May. The location of comet C/2015 G2 MASTER is shown with a circle. You will probably need binoculars to see it. Similar views will be seen elsewhere in Australia at
equivalent local times. (click on image to embiggen).

Comet C/2015 G2 Master is now in the evening sky and high enough above the horizon to be readily seen. It should be around magnitude 6, just on the threshold of unaided eye visibility, but is best viewed with binoculars and telescopes. In binoculars the comet will be a fuzzy blob, and decent telescopes may show the thin tail see in astrophotographs.

The comet will move rapidly up through Lepus heading for Canis Major this week. A spotters map suitable for printing in black and white is here.

There are lots
of interesting things in the sky to view with a telescope. Especially
with Jupiter, Venus and Saturn in the sky. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Wednesday, May 06, 2015

Aurora Watch (6-7 May)

An Aurora Watch and a geomagnetic alert has been issued by the Australian IPS
for the 6th to 7th due to an anticipated impact from a Coronal Mass Ejection.
This could translate into aurora at any time during the 6th to 7th (quite
possibly after midnight on the 6th). Geomagnetic activity is rated at active
with the possibility of a minor geomagnetic storm.

Aurora, if they occur,
are likely to be seen only in Tasmania (possibly Victoria if the minor storm
eventuates), but in the last unexpected storm they were seen in WA as
well.

Aurora can occur at any time after nightfall (although around
midnight or just after seems to be common). Dark sky sites have the best chance
of seeing anything, and always allow around 5 minutes for your eyes to become
dark adapted.

As always look to the south for shifting red/green glows, beams
have been reported consistently over the last few aurora and a large green
"blob" has been seen.

Catch a Series of Bright International Space Station Passes (6-11 May 2015)

The ISS passes near the Venus, looking north-west as seen from Melbourne on the evening of Thursday 7 May
at 19:04 AEST. Simulated in Stellarium (the ISS will actually be a
bright dot), click to embiggen.

The ISS passes near the Venus, looking north-west as seen from Adelaide on the evening of Thursday 7 May
at 18:33 ACST. Simulated in Stellarium (the ISS will actually be a
bright dot), click to embiggen

The ISS passes near the Venus, looking north-west as seen from Perth on the evening of Thursday 7 May
at 18:33 AWST. Simulated in Stellarium (the ISS will actually be a
bright dot), click to embiggen

All sky chart showing local times from Heavens Above for Thursday 7 May for Melbourne.

All sky chart showing local times from Heavens Above for Thursday 7 May for Adelaide.

All sky chart showing local times from Heavens Above for Thursday 7 May for Perth.

Starting tonight there are a series of bright evening passes of the
International Space Station lasting a week. For many places in Australia
this series has the ISS gliding either through or under Orion, depending on where you are, and coming close
to bright Venus on the 7th (Thursday). Some of the passes are very short although
bright as the ISS enters Earth's shadow.

When and what you will see is VERY location dependent, so you need to use either Heavens Above or CalSky
to get site specific predictions for your location (I'm using
Melbourne, Adelaide and Perth as examples, for example, the view from
Melbourne is different from that of Adelaide and Perth on the
night of the 7th). Even the difference between the city centre and the
suburbs can mean the difference between seeing the ISS go through
Orion's belt or just below it.

Start looking several minutes before the pass is going to start to get
yourself oriented and your eyes dark adapted. Be patient, on the night
there may be slight differences in the time of the ISS appearing due to
orbit changes not picked up by the predictions. The ISS will be moving moderately fast when it passes near Venus, so be alert.

Tuesday, May 05, 2015

The Sky This Week - Thursday May 7 to Thursday May 14

The Last Quarter Moon is Monday May 11. Venus
is prominent in
the twilight evening sky. Jupiter is the
brightest object in the evening sky once Venus has set. Saturn is in the
head of the Scorpion and is easily visible in the evening. Mercury is difficult to view in the twilight. Eta
Aquariid meteor shower May 7-9. The International Space Station passes Venus as seen from many locations on the 7th.

The Last Quarter Moon is Monday May 11. The Moon is at perigee, when it is closest to the Earth, on the 15th.

Evening sky on Thursday May 7 looking west as seen from Adelaide
at 17:55 (5:55 pm) ACST in South Australia. Venus is obvious in the
early evening sky. Mercury is just on the horizon Similar views will be
seen
elsewhere
at the equivalent local time (click to embiggen).

Venus
is easy to see above the western horizon in the twilight. At nautical
twilight, an hour after sunset, it is around two hand-spans
above the horizon, and still visible at astronomical twilight.

During the week Venus draws closer to the stars Castor and Pollux, heading for a meeting with Jupiter
later next month.

Early evening sky on Saturday May 9 looking north-west as seen from
Adelaide
at 18:30 ACST showing Venus and Jupiter. Jupiter is the brightest object
above the north-western horizon once Venus has set. (click
to embiggen).

Jupiter
is easily seen in the evening sky. It is the brightest object
above the
northern horizon when twilight ends, and continues into the north-western sky as the night goes on. It is between the bright
star Regulus in
the sickle of Leo (this forms the head of the constellation of the
Lion) and Pollux in Cancer. It is also not far from the rather nice Beehive cluster in
Cancer, and looks very good in binoculars. Jupiter, Venus and Pollux form a line in the sky.

Jupiter was at
opposition, when it is biggest and brightest in our sky, on 7 February,
but
it will be an excellent object for many weeks to come. Jupiter is
visible for most of the night, setting just after midnight, and is high
enough for telescopic observation once twilight is over.
Jupiter's Moons will be putting on a good
display in both binoculars and small telescopes.

Evening sky on Saturday May 9 looking east as seen from
Adelaide
at 21:00 ACST. Saturn is easily visible above the horizon in the head of the Scorpion. The
inset shows the telescopic view of Saturn at this time. (click
to embiggen).

Saturn
is now easily visible around 9 pm near the head of the constellation of the Scorpion not far
from the bright red star Antares. The sight of the distinctive
constellation of the Scorpion curled above the horizon, with bright
Saturn in its head, is very nice indeed.

While Saturn is readily visible from around 20:00, it is best for
telescope observation from around 22:00 into the morning hours. Morning sky on Thursday May 8 looking east as seen from Adelaide
at 4:00 am ACST. The radiant of the eta Aquariid meteor shower is
shown. Similar views will be seen throughout Australia at equivalent
local times. (click
to embiggen).

The eta Aquariids meteor shower, the debris from Halleys comet, will peak on May 6 UT . However, good rates (compared to the peak) will be seen from Australia on the mornings of the 7th and 8th.

Unfortunately, the waning but nearly full Moon will significantly
interfere with viewing meteors this year. People in the suburbs should
see a meteor around once every 9 minutes,
and in the country about once every 6 minutes. The
radiant of the shower is about five handspans up from the eastern
horizon, and three handspans to the left of due east at 4 am (see
spotter chart at 4 am above).

When looking, be sure to let your eyes adjust for at least
5 minutes so your eyes can be properly adapted to the dark. Don't look
directly at the radiant site, because the meteors will often start
their "burn" some distance from it, but around a handspan up or to the
side. Be patient, although you should see an average of
a meteor every six minutes, a whole stretch of time can go by
without a meteor, then a whole bunch turn up one after the other.

There are lots
of interesting things in the sky to view with a telescope. Especially
with Jupiter, Venus and Saturn in the sky. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Monday, May 04, 2015

eta Aquariid Meteor Shower 7-9 May, 2015

Morning sky on Thursday May 7 looking east as seen from Adelaide
at 4:00 am ACST. The radiant of the eta Aquariid meteor shower is
shown. Similar views will be seen elsewhere in Australia at the
equivalent local time. (click
to embiggen).

The eta Aquariids meteor shower, the debris from Halleys comet, will peak on May 6 UT . However, the best (but weak) rates will be seen from Australia on the mornings of the 7th and 8th.

Unfortunately, the waning but nearly full Moon will significantly
interfere with viewing meteors this year. People in the suburbs should
see a meteor around once every 9 minutes,
and in the country about once every 6 minutes. The
radiant of the shower is about five hand-spans up from the eastern
horizon, and three hand-spans to the left of due east at 4 am (see
spotter chart at 4 am above).

The figure ZHR is zenithal hourly rate. This is the number of meteors
that a single observer would see per hour if the shower's "point of
origin", or radiant, were at the zenith and the sky were dark enough
for 6.5-magnitude
stars to be visible to the naked eye.

In practise, you will never see
this many meteors as the radiant will be some distance below the zenith.
Also, unless you are out deep in the countryside, the darkness will be
less than ideal. How
many are you likely to see in reality? I discuss this further down,
lets talk about when to see them first.

Although the actual peak is on 6th at 17:00 AEST, for Australia the best
time to see the eta-Aquarids is in the early morning of the 7th, 8th
and 9th. This year the first quarter Moon sets long before the radiant
rises, so you should have almost ideal observing conditions if the cloud
stays away.

How many will be seen on the 7th is not clear, but very good rates were
seen last year, and dark sky sites may possibly see one meteor every
two minutes or so. There were many bright ones reported with
persistent trains. People in the suburbs may be will see less, but at
least one every 6 minutes should be possible.

People in the suburbs should see a meteor around once every 6 minutes,
and in the country about once every 3 minutes on the 7th, a bit more
on the 8th and around the same rates as the 7th on the 9th. The
radiant of the shower is about five handspans up from the eastern
horizon, and three handspans to the left of due east at 4 am (see above for a spotter chart at 5 am).

When looking, be sure to let your eyes adjust for at least
5 minutes so your eyes can be properly adapted to the dark. Don't look
directly at the radiant site, because the meteors will often start
their "burn" some distance from it, but around a handspan up or to the
side. Be patient, although you should see an average of
a meteor every six to three minutes, a whole stretch of time can go by
without a meteor, then a whole bunch turn up one after the other.

Make
yourself comfortable, choose an observing site that has little to
obstruct the eastern horizon, have a comfortable chair to sit in (a
banana lounger is best), or blankets and pillows. Rug up against the cold. A hot Thermos of
something to drink and plenty of
mosquito protection will complete your observing preparations. As well
as meteors, keep an eye out for satellites (see Heavens Above for predictions from your site).

Use the NASA meteor shower flux estimator for
an estimate of what the shower will be like from your location (you
may need to enter your longitude and latitude, surprisingly, while
Adelaide and Brisbane are hard wired in, Sydney and Melbourne are not). See the image to the left for typical output. The peak is rather sharp and not very high, due to the Moonlight.

You
need to choose 31 Eta Aquariids and remember to set the date to 6-7, 7-8 or
8-9 May 2015. You can follow the progress of the shower at the IMO live Aquariid site.

Venus
is readily visible in the evening sky. Venus is close to the crescent Moon on the 21st and forms a nice line-up with Jupiter.

Saturn
is at opposition, when it is biggest and brightest as seen from Earth,on the 23rd. It is in the head of the constellation
of Scorpius, the Scorpion. Saturn is close to the waning Moon on the 5th.